Welfare reform and changes in immigrants' eligibility may lead to significant reductions in Medicaid caseloads, even though many states are expanding Medicaid eligibility rules to accommodate changes under the new welfare programs. In 1996, for the first time in almost a decade, Medicaid participation of adults and children fell about 2 percent, and further reductions seem likely in 1997. The gradual restrictions on new immigrants also will affect future caseloads. Although new initiatives such as the State Children's Health Insurance Program (CHIP) should expand health coverage for children, the welfare reform and immigration changes will disproportionately lead to loss of insurance among adults.